Erhöhung der Biodiversität durch Entfernung von Gehölzbeständen in Küstendünen?
Zusammenfassung der Projektergebnisse
In dune areas along the Sefton coast, north of Liverpool, the comparison of areas with Hippophae rhamnoides scrub, areas with scrub removal and dune grassland areas, known to be without scrub since decades, showed differences in species richness. Shrub removal regenerated landscape heterogeneity of coastal dune areas. Enhanced landscape heterogeneity (y-diversity) increased total species-richness. Species diversity at the local scale, the ß-diversity expressed as Sorensen index, was not significantly higher in areas where scrub has been removed. In contrast, areas with scrub removal are more heterogeneous, probably due to effects of the management, than shrubland and grassland plots, respectively. Species diversity at the small scale was caused by intermediate levels of environmental heterogeneity, reflected as intermediate values of the l-Sorensen index. Due to nitrogen fixation by Hippophae rhamnoides and the release after scrub removal, the nitrogen content in the soils of removed areas reached highest values. However, most nitrogenous species occurred in the shrubland. Nevertheless, some scrub patches should be remained in the dunes, both offering habitats for many animals and to enhance the number of landscape patches. The results can be used for further management in the dune areas. Recommended is the evaluation of a management plan with scrub areas of different size, as stepping stones for animals and to enrich landscape as well as species diversity. Further management will be necessary, whereas the usage of herbicides should be stopped. Cutting and other manual removal should be preferred. The nitrogen content was enhanced in the scrub removed areas; surprisingly the number of nitrophiluous species was not higher than in the Hippophaö rhamnoides scrub. Probably, the abundances of species like Chamerion angustifolium are enhanced, which is not tested yet. The impact of lots of people in the dunes was much more than suspected. Some areas were so much affected, that more or less no undisturbed dunes slopes occurred, so that investigations considering this project were not possible. In general surprising was the amount and effort that the local authorities spend for the management of dunes in total. Moreover, management plans combined dry and wet dune areas, and incorporate ecological relationships of the total dune area.
Projektbezogene Publikationen (Auswahl)
- (2010) Is plant biodiversity maintained by scrub removal in coastal dunes? Sand Dune and Shingle Network Newsletter 9, 9
Isermann, M.
